#include "test_tcp.h"

#include "lwip/tcp_impl.h"
#include "lwip/stats.h"
#include "tcp_helper.h"

#ifdef _MSC_VER
	#pragma warning(disable: 4307) /* we explicitly wrap around TCP seqnos */
#endif

#if !LWIP_STATS || !TCP_STATS || !MEMP_STATS
	#error "This tests needs TCP- and MEMP-statistics enabled"
#endif
#if TCP_SND_BUF <= TCP_WND
	#error "This tests needs TCP_SND_BUF to be > TCP_WND"
#endif

static u8_t test_tcp_timer;

/* our own version of tcp_tmr so we can reset fast/slow timer state */
static void
test_tcp_tmr(void)
{
	tcp_fasttmr();

	if(++test_tcp_timer & 1) {
		tcp_slowtmr();
	}
}

/* Setups/teardown functions */

static void
tcp_setup(void)
{
	/* reset iss to default (6510) */
	tcp_ticks = 0;
	tcp_ticks = 0 - (tcp_next_iss() - 6510);
	tcp_next_iss();
	tcp_ticks = 0;

	test_tcp_timer = 0;
	tcp_remove_all();
}

static void
tcp_teardown(void)
{
	netif_list = NULL;
	tcp_remove_all();
}


/* Test functions */

/** Call tcp_new() and tcp_abort() and test memp stats */
START_TEST(test_tcp_new_abort)
{
	struct tcp_pcb* pcb;
	LWIP_UNUSED_ARG(_i);

	fail_unless(lwip_stats.memp[MEMP_TCP_PCB].used == 0);

	pcb = tcp_new();
	fail_unless(pcb != NULL);

	if(pcb != NULL) {
		fail_unless(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
		tcp_abort(pcb);
		fail_unless(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
	}
}
END_TEST

/** Create an ESTABLISHED pcb and check if receive callback is called */
START_TEST(test_tcp_recv_inseq)
{
	struct test_tcp_counters counters;
	struct tcp_pcb* pcb;
	struct pbuf* p;
	char data[] = {1, 2, 3, 4};
	ip_addr_t remote_ip, local_ip;
	u16_t data_len;
	u16_t remote_port = 0x100, local_port = 0x101;
	struct netif netif;
	LWIP_UNUSED_ARG(_i);

	/* initialize local vars */
	memset(&netif, 0, sizeof(netif));
	IP4_ADDR(&local_ip, 192, 168, 1, 1);
	IP4_ADDR(&remote_ip, 192, 168, 1, 2);
	data_len = sizeof(data);
	/* initialize counter struct */
	memset(&counters, 0, sizeof(counters));
	counters.expected_data_len = data_len;
	counters.expected_data = data;

	/* create and initialize the pcb */
	pcb = test_tcp_new_counters_pcb(&counters);
	EXPECT_RET(pcb != NULL);
	tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);

	/* create a segment */
	p = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);
	EXPECT(p != NULL);

	if(p != NULL) {
		/* pass the segment to tcp_input */
		test_tcp_input(p, &netif);
		/* check if counters are as expected */
		EXPECT(counters.close_calls == 0);
		EXPECT(counters.recv_calls == 1);
		EXPECT(counters.recved_bytes == data_len);
		EXPECT(counters.err_calls == 0);
	}

	/* make sure the pcb is freed */
	EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
	tcp_abort(pcb);
	EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
END_TEST

/** Provoke fast retransmission by duplicate ACKs and then recover by ACKing all sent data.
 * At the end, send more data. */
START_TEST(test_tcp_fast_retx_recover)
{
	struct netif netif;
	struct test_tcp_txcounters txcounters;
	struct test_tcp_counters counters;
	struct tcp_pcb* pcb;
	struct pbuf* p;
	char data1[] = { 1,  2,  3,  4};
	char data2[] = { 5,  6,  7,  8};
	char data3[] = { 9, 10, 11, 12};
	char data4[] = {13, 14, 15, 16};
	char data5[] = {17, 18, 19, 20};
	char data6[] = {21, 22, 23, 24};
	ip_addr_t remote_ip, local_ip, netmask;
	u16_t remote_port = 0x100, local_port = 0x101;
	err_t err;
	LWIP_UNUSED_ARG(_i);

	/* initialize local vars */
	IP4_ADDR(&local_ip,  192, 168,   1, 1);
	IP4_ADDR(&remote_ip, 192, 168,   1, 2);
	IP4_ADDR(&netmask,   255, 255, 255, 0);
	test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
	memset(&counters, 0, sizeof(counters));

	/* create and initialize the pcb */
	pcb = test_tcp_new_counters_pcb(&counters);
	EXPECT_RET(pcb != NULL);
	tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
	pcb->mss = TCP_MSS;
	/* disable initial congestion window (we don't send a SYN here...) */
	pcb->cwnd = pcb->snd_wnd;

	/* send data1 */
	err = tcp_write(pcb, data1, sizeof(data1), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	EXPECT_RET(txcounters.num_tx_calls == 1);
	EXPECT_RET(txcounters.num_tx_bytes == sizeof(data1) + sizeof(struct tcp_hdr) + sizeof(struct ip_hdr));
	memset(&txcounters, 0, sizeof(txcounters));
	/* "recv" ACK for data1 */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 4, TCP_ACK);
	EXPECT_RET(p != NULL);
	test_tcp_input(p, &netif);
	EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(pcb->unacked == NULL);
	/* send data2 */
	err = tcp_write(pcb, data2, sizeof(data2), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	EXPECT_RET(txcounters.num_tx_calls == 1);
	EXPECT_RET(txcounters.num_tx_bytes == sizeof(data2) + sizeof(struct tcp_hdr) + sizeof(struct ip_hdr));
	memset(&txcounters, 0, sizeof(txcounters));
	/* duplicate ACK for data1 (data2 is lost) */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	EXPECT_RET(p != NULL);
	test_tcp_input(p, &netif);
	EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(pcb->dupacks == 1);
	/* send data3 */
	err = tcp_write(pcb, data3, sizeof(data3), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/* nagle enabled, no tx calls */
	EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(txcounters.num_tx_bytes == 0);
	memset(&txcounters, 0, sizeof(txcounters));
	/* 2nd duplicate ACK for data1 (data2 and data3 are lost) */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	EXPECT_RET(p != NULL);
	test_tcp_input(p, &netif);
	EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(pcb->dupacks == 2);
	/* queue data4, don't send it (unsent-oversize is != 0) */
	err = tcp_write(pcb, data4, sizeof(data4), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	/* 3nd duplicate ACK for data1 (data2 and data3 are lost) -> fast retransmission */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	EXPECT_RET(p != NULL);
	test_tcp_input(p, &netif);
	/*EXPECT_RET(txcounters.num_tx_calls == 1);*/
	EXPECT_RET(pcb->dupacks == 3);
	memset(&txcounters, 0, sizeof(txcounters));
	/* TODO: check expected data?*/

	/* send data5, not output yet */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	/*err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);*/
	EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(txcounters.num_tx_bytes == 0);
	memset(&txcounters, 0, sizeof(txcounters));
	{
		int i = 0;

		do {
			err = tcp_write(pcb, data6, TCP_MSS, TCP_WRITE_FLAG_COPY);
			i++;
		} while(err == ERR_OK);

		EXPECT_RET(err != ERR_OK);
	}
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/*EXPECT_RET(txcounters.num_tx_calls == 0);
	EXPECT_RET(txcounters.num_tx_bytes == 0);*/
	memset(&txcounters, 0, sizeof(txcounters));

	/* send even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/* ...and even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/* ...and even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/* ...and even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);

	/* send ACKs for data2 and data3 */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 12, TCP_ACK);
	EXPECT_RET(p != NULL);
	test_tcp_input(p, &netif);
	/*EXPECT_RET(txcounters.num_tx_calls == 0);*/

	/* ...and even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	/* ...and even more data */
	err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);

#if 0
	/* create expected segment */
	p1 = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);
	EXPECT_RET(p != NULL);

	if(p != NULL) {
		/* pass the segment to tcp_input */
		test_tcp_input(p, &netif);
		/* check if counters are as expected */
		EXPECT_RET(counters.close_calls == 0);
		EXPECT_RET(counters.recv_calls == 1);
		EXPECT_RET(counters.recved_bytes == data_len);
		EXPECT_RET(counters.err_calls == 0);
	}

#endif
	/* make sure the pcb is freed */
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
	tcp_abort(pcb);
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
END_TEST

static u8_t tx_data[TCP_WND * 2];

static void
check_seqnos(struct tcp_seg* segs, int num_expected, u32_t* seqnos_expected)
{
	struct tcp_seg* s = segs;
	int i;

	for(i = 0; i < num_expected; i++, s = s->next) {
		EXPECT_RET(s != NULL);
		EXPECT(s->tcphdr->seqno == htonl(seqnos_expected[i]));
	}

	EXPECT(s == NULL);
}

/** Send data with sequence numbers that wrap around the u32_t range.
 * Then, provoke fast retransmission by duplicate ACKs and check that all
 * segment lists are still properly sorted. */
START_TEST(test_tcp_fast_rexmit_wraparound)
{
	struct netif netif;
	struct test_tcp_txcounters txcounters;
	struct test_tcp_counters counters;
	struct tcp_pcb* pcb;
	struct pbuf* p;
	ip_addr_t remote_ip, local_ip, netmask;
	u16_t remote_port = 0x100, local_port = 0x101;
	err_t err;
#define SEQNO1 (0xFFFFFF00 - TCP_MSS)
#define ISS    6510
	u16_t i, sent_total = 0;
	u32_t seqnos[] = {
		SEQNO1,
		SEQNO1 + (1 * TCP_MSS),
		SEQNO1 + (2 * TCP_MSS),
		SEQNO1 + (3 * TCP_MSS),
		SEQNO1 + (4 * TCP_MSS),
		SEQNO1 + (5 * TCP_MSS)
	};
	LWIP_UNUSED_ARG(_i);

	for(i = 0; i < sizeof(tx_data); i++) {
		tx_data[i] = (u8_t)i;
	}

	/* initialize local vars */
	IP4_ADDR(&local_ip,  192, 168,   1, 1);
	IP4_ADDR(&remote_ip, 192, 168,   1, 2);
	IP4_ADDR(&netmask,   255, 255, 255, 0);
	test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
	memset(&counters, 0, sizeof(counters));

	/* create and initialize the pcb */
	tcp_ticks = SEQNO1 - ISS;
	pcb = test_tcp_new_counters_pcb(&counters);
	EXPECT_RET(pcb != NULL);
	EXPECT(pcb->lastack == SEQNO1);
	tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
	pcb->mss = TCP_MSS;
	/* disable initial congestion window (we don't send a SYN here...) */
	pcb->cwnd = 2 * TCP_MSS;

	/* send 6 mss-sized segments */
	for(i = 0; i < 6; i++) {
		err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
		EXPECT_RET(err == ERR_OK);
		sent_total += TCP_MSS;
	}

	check_seqnos(pcb->unsent, 6, seqnos);
	EXPECT(pcb->unacked == NULL);
	err = tcp_output(pcb);
	EXPECT(txcounters.num_tx_calls == 2);
	EXPECT(txcounters.num_tx_bytes == 2 * (TCP_MSS + 40U));
	memset(&txcounters, 0, sizeof(txcounters));

	check_seqnos(pcb->unacked, 2, seqnos);
	check_seqnos(pcb->unsent, 4, &seqnos[2]);

	/* ACK the first segment */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, TCP_MSS, TCP_ACK);
	test_tcp_input(p, &netif);
	/* ensure this didn't trigger a retransmission */
	EXPECT(txcounters.num_tx_calls == 1);
	EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
	memset(&txcounters, 0, sizeof(txcounters));
	check_seqnos(pcb->unacked, 2, &seqnos[1]);
	check_seqnos(pcb->unsent, 3, &seqnos[3]);

	/* 3 dupacks */
	EXPECT(pcb->dupacks == 0);
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	test_tcp_input(p, &netif);
	EXPECT(txcounters.num_tx_calls == 0);
	EXPECT(pcb->dupacks == 1);
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	test_tcp_input(p, &netif);
	EXPECT(txcounters.num_tx_calls == 0);
	EXPECT(pcb->dupacks == 2);
	/* 3rd dupack -> fast rexmit */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	test_tcp_input(p, &netif);
	EXPECT(pcb->dupacks == 3);
	EXPECT(txcounters.num_tx_calls == 4);
	memset(&txcounters, 0, sizeof(txcounters));
	EXPECT(pcb->unsent == NULL);
	check_seqnos(pcb->unacked, 5, &seqnos[1]);

	/* make sure the pcb is freed */
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
	tcp_abort(pcb);
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
END_TEST

/** Send data with sequence numbers that wrap around the u32_t range.
 * Then, provoke RTO retransmission and check that all
 * segment lists are still properly sorted. */
START_TEST(test_tcp_rto_rexmit_wraparound)
{
	struct netif netif;
	struct test_tcp_txcounters txcounters;
	struct test_tcp_counters counters;
	struct tcp_pcb* pcb;
	ip_addr_t remote_ip, local_ip, netmask;
	u16_t remote_port = 0x100, local_port = 0x101;
	err_t err;
#define SEQNO1 (0xFFFFFF00 - TCP_MSS)
#define ISS    6510
	u16_t i, sent_total = 0;
	u32_t seqnos[] = {
		SEQNO1,
		SEQNO1 + (1 * TCP_MSS),
		SEQNO1 + (2 * TCP_MSS),
		SEQNO1 + (3 * TCP_MSS),
		SEQNO1 + (4 * TCP_MSS),
		SEQNO1 + (5 * TCP_MSS)
	};
	LWIP_UNUSED_ARG(_i);

	for(i = 0; i < sizeof(tx_data); i++) {
		tx_data[i] = (u8_t)i;
	}

	/* initialize local vars */
	IP4_ADDR(&local_ip,  192, 168,   1, 1);
	IP4_ADDR(&remote_ip, 192, 168,   1, 2);
	IP4_ADDR(&netmask,   255, 255, 255, 0);
	test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
	memset(&counters, 0, sizeof(counters));

	/* create and initialize the pcb */
	tcp_ticks = 0;
	tcp_ticks = 0 - tcp_next_iss();
	tcp_ticks = SEQNO1 - tcp_next_iss();
	pcb = test_tcp_new_counters_pcb(&counters);
	EXPECT_RET(pcb != NULL);
	EXPECT(pcb->lastack == SEQNO1);
	tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
	pcb->mss = TCP_MSS;
	/* disable initial congestion window (we don't send a SYN here...) */
	pcb->cwnd = 2 * TCP_MSS;

	/* send 6 mss-sized segments */
	for(i = 0; i < 6; i++) {
		err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
		EXPECT_RET(err == ERR_OK);
		sent_total += TCP_MSS;
	}

	check_seqnos(pcb->unsent, 6, seqnos);
	EXPECT(pcb->unacked == NULL);
	err = tcp_output(pcb);
	EXPECT(txcounters.num_tx_calls == 2);
	EXPECT(txcounters.num_tx_bytes == 2 * (TCP_MSS + 40U));
	memset(&txcounters, 0, sizeof(txcounters));

	check_seqnos(pcb->unacked, 2, seqnos);
	check_seqnos(pcb->unsent, 4, &seqnos[2]);

	/* call the tcp timer some times */
	for(i = 0; i < 10; i++) {
		test_tcp_tmr();
		EXPECT(txcounters.num_tx_calls == 0);
	}

	/* 11th call to tcp_tmr: RTO rexmit fires */
	test_tcp_tmr();
	EXPECT(txcounters.num_tx_calls == 1);
	check_seqnos(pcb->unacked, 1, seqnos);
	check_seqnos(pcb->unsent, 5, &seqnos[1]);

	/* fake greater cwnd */
	pcb->cwnd = pcb->snd_wnd;
	/* send more data */
	err = tcp_output(pcb);
	EXPECT(err == ERR_OK);
	/* check queues are sorted */
	EXPECT(pcb->unsent == NULL);
	check_seqnos(pcb->unacked, 6, seqnos);

	/* make sure the pcb is freed */
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
	tcp_abort(pcb);
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
END_TEST

/** Provoke fast retransmission by duplicate ACKs and then recover by ACKing all sent data.
 * At the end, send more data. */
static void test_tcp_tx_full_window_lost(u8_t zero_window_probe_from_unsent)
{
	struct netif netif;
	struct test_tcp_txcounters txcounters;
	struct test_tcp_counters counters;
	struct tcp_pcb* pcb;
	struct pbuf* p;
	ip_addr_t remote_ip, local_ip, netmask;
	u16_t remote_port = 0x100, local_port = 0x101;
	err_t err;
	u16_t sent_total, i;
	u8_t expected = 0xFE;

	for(i = 0; i < sizeof(tx_data); i++) {
		u8_t d = (u8_t)i;

		if(d == 0xFE) {
			d = 0xF0;
		}

		tx_data[i] = d;
	}

	if(zero_window_probe_from_unsent) {
		tx_data[TCP_WND] = expected;
	} else {
		tx_data[0] = expected;
	}

	/* initialize local vars */
	IP4_ADDR(&local_ip,  192, 168,   1, 1);
	IP4_ADDR(&remote_ip, 192, 168,   1, 2);
	IP4_ADDR(&netmask,   255, 255, 255, 0);
	test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
	memset(&counters, 0, sizeof(counters));
	memset(&txcounters, 0, sizeof(txcounters));

	/* create and initialize the pcb */
	pcb = test_tcp_new_counters_pcb(&counters);
	EXPECT_RET(pcb != NULL);
	tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
	pcb->mss = TCP_MSS;
	/* disable initial congestion window (we don't send a SYN here...) */
	pcb->cwnd = pcb->snd_wnd;

	/* send a full window (minus 1 packets) of TCP data in MSS-sized chunks */
	sent_total = 0;

	if((TCP_WND - TCP_MSS) % TCP_MSS != 0) {
		u16_t initial_data_len = (TCP_WND - TCP_MSS) % TCP_MSS;
		err = tcp_write(pcb, &tx_data[sent_total], initial_data_len, TCP_WRITE_FLAG_COPY);
		EXPECT_RET(err == ERR_OK);
		err = tcp_output(pcb);
		EXPECT_RET(err == ERR_OK);
		EXPECT(txcounters.num_tx_calls == 1);
		EXPECT(txcounters.num_tx_bytes == initial_data_len + 40U);
		memset(&txcounters, 0, sizeof(txcounters));
		sent_total += initial_data_len;
	}

	for(; sent_total < (TCP_WND - TCP_MSS); sent_total += TCP_MSS) {
		err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
		EXPECT_RET(err == ERR_OK);
		err = tcp_output(pcb);
		EXPECT_RET(err == ERR_OK);
		EXPECT(txcounters.num_tx_calls == 1);
		EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
		memset(&txcounters, 0, sizeof(txcounters));
	}

	EXPECT(sent_total == (TCP_WND - TCP_MSS));

	/* now ACK the packet before the first */
	p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
	test_tcp_input(p, &netif);
	/* ensure this didn't trigger a retransmission */
	EXPECT(txcounters.num_tx_calls == 0);
	EXPECT(txcounters.num_tx_bytes == 0);

	EXPECT(pcb->persist_backoff == 0);
	/* send the last packet, now a complete window has been sent */
	err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
	sent_total += TCP_MSS;
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	EXPECT(txcounters.num_tx_calls == 1);
	EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
	memset(&txcounters, 0, sizeof(txcounters));
	EXPECT(pcb->persist_backoff == 0);

	if(zero_window_probe_from_unsent) {
		/* ACK all data but close the TX window */
		p = tcp_create_rx_segment_wnd(pcb, NULL, 0, 0, TCP_WND, TCP_ACK, 0);
		test_tcp_input(p, &netif);
		/* ensure this didn't trigger any transmission */
		EXPECT(txcounters.num_tx_calls == 0);
		EXPECT(txcounters.num_tx_bytes == 0);
		EXPECT(pcb->persist_backoff == 1);
	}

	/* send one byte more (out of window) -> persist timer starts */
	err = tcp_write(pcb, &tx_data[sent_total], 1, TCP_WRITE_FLAG_COPY);
	EXPECT_RET(err == ERR_OK);
	err = tcp_output(pcb);
	EXPECT_RET(err == ERR_OK);
	EXPECT(txcounters.num_tx_calls == 0);
	EXPECT(txcounters.num_tx_bytes == 0);
	memset(&txcounters, 0, sizeof(txcounters));

	if(!zero_window_probe_from_unsent) {
		/* no persist timer unless a zero window announcement has been received */
		EXPECT(pcb->persist_backoff == 0);
	} else {
		EXPECT(pcb->persist_backoff == 1);

		/* call tcp_timer some more times to let persist timer count up */
		for(i = 0; i < 4; i++) {
			test_tcp_tmr();
			EXPECT(txcounters.num_tx_calls == 0);
			EXPECT(txcounters.num_tx_bytes == 0);
		}

		/* this should trigger the zero-window-probe */
		txcounters.copy_tx_packets = 1;
		test_tcp_tmr();
		txcounters.copy_tx_packets = 0;
		EXPECT(txcounters.num_tx_calls == 1);
		EXPECT(txcounters.num_tx_bytes == 1 + 40U);
		EXPECT(txcounters.tx_packets != NULL);

		if(txcounters.tx_packets != NULL) {
			u8_t sent;
			u16_t ret;
			ret = pbuf_copy_partial(txcounters.tx_packets, &sent, 1, 40U);
			EXPECT(ret == 1);
			EXPECT(sent == expected);
		}

		if(txcounters.tx_packets != NULL) {
			pbuf_free(txcounters.tx_packets);
			txcounters.tx_packets = NULL;
		}
	}

	/* make sure the pcb is freed */
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
	tcp_abort(pcb);
	EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}

START_TEST(test_tcp_tx_full_window_lost_from_unsent)
{
	LWIP_UNUSED_ARG(_i);
	test_tcp_tx_full_window_lost(1);
}
END_TEST

START_TEST(test_tcp_tx_full_window_lost_from_unacked)
{
	LWIP_UNUSED_ARG(_i);
	test_tcp_tx_full_window_lost(0);
}
END_TEST

/** Create the suite including all tests for this module */
Suite*
tcp_suite(void)
{
	TFun tests[] = {
		test_tcp_new_abort,
		test_tcp_recv_inseq,
		test_tcp_fast_retx_recover,
		test_tcp_fast_rexmit_wraparound,
		test_tcp_rto_rexmit_wraparound,
		test_tcp_tx_full_window_lost_from_unacked,
		test_tcp_tx_full_window_lost_from_unsent
	};
	return create_suite("TCP", tests, sizeof(tests) / sizeof(TFun), tcp_setup, tcp_teardown);
}
